Thrust washers are used to prevent movement along the axis of a shaft and to support an axial load on the shaft. They are usually made of steel, bronze, plastic, or other useful material, and are often employed in high wear applications, such as motors, winches, pumps, and axle assemblies.
In a typical axle assembly of a machine, an axle, such as, for example, a rear axle, is rigidly connected to a first end of an A-frame structure. A second end of the A-frame structure or, more specifically, the apex of the A-frame structure is pivotably connected to a main frame of the machine at a clevis joint. The clevis extends from the center of a tube having two end plates welded to opposing inner surfaces of the main frame. The clevis joint includes two parallel plates having central openings configured to receive a pin assembly.
The apex of the A-frame structure is positioned between the two clevis plates, and a pin is passed through both the openings in the clevis plates and the apex to secure the A-frame in place. A spherical plain bearing is employed to allow some rotational movement of the A-frame in relation to the clevis joint. Two thrust washers are positioned about the pins on either side of the spherical bearing to take up space along the axis of the pin.
To facilitate assembly, a thickness of the A-frame apex, including the spherical plain bearing and thrust washers, must be less than the clearance between the clevis plates. Once the A-frame apex is secure, however, this clearance provides space along the axis of the clevis joint along which the joint elements may transversely slide. This movement may cause impact loading, which may, in turn, damage the elements of the joint, particularly the bearing.
It is common to use shims and plates to reduce clearance within the joint. However, introducing additional parts to the joint adds time and cost to the assembly process. Another similar solution includes a set of steel wedges that take up clearance existing along an axis of a joint. Specifically, U.S. Pat. No. 4,690,573 includes a take up adjuster that may be placed between a thrust washer and a bracket. The take up adjuster includes a bolt or nut, which can be adjusted to force two sloped wedge plates toward one another. As these wedge plates come together, they contact a second set of wedge plates and force those wedge plates upward into space that may exist between the thrust washer and bracket. This reference does not, however, contemplate a thrust washer that expands to reduce the clearance existing after the joint is assembled.
The present disclosure is directed to one or more of the problems set forth above.